The present invention relates to apparatus for cleaning pipelines, especially for cleaning flexible and/or rigid conduits for beer and/or other beverages. More particularly, the invention relates to improvements in apparatus for cleaning pipelines by means of a liquid cleaning agent in conjunction with discrete cleaning elements in the form of small spherical sponges, glass balls, pieces of synthetic plastic material or the like. Still more particularly, the invention relates to improvements in cleaning apparatus of the type wherein the direction of flow of cleaning agent and cleaning elements through a pipeline can be reversed by a four-way valve.
Commonly owned German Auslegeschrift No. 17 82 136 discloses a cleaning apparatus wherein a reversible four-way valve has a body with an inlet for fresh cleaning agent, an outlet for spent cleaning agent and two ports which can be connected with the ends of a pipeline. The valving element is a reciprocable piston which can be shifted back and forth by a set of cleaning elements which travel through the pipeline to impinge upon one end face of the piston whereby the piston is caused to change its position and to change the direction of flow of cleaning agent through the pipeline. The cleaning elements then impinge upon the other end face of the piston with a renewed change in the position of the piston. The same procedure is repeated again and again until the cleaning operation is completed. In one of its positions, the piston causes the cleaning agent to flow from the inlet into one of the ports, through the pipeline, through the other port and into the outlet. When in the other position, the piston causes the freshly admitted cleaning agent to flow into the other port, through the pipeline, back into the body of the valve through the one port and into the outlet. The cleaning elements migrate back and forth by advancing through the pipeline from one end face of the piston to the other end face, back to the one end face and so on. The apparatus which is disclosed in the German publication further comprises at least one housing with a larger-diameter end attached to the body of the valve so as to communicate with one of the ports, and a smaller-diameter end connected to the respective end of a pipeline which requires cleaning. The pipeline is a flexible conduit or a rigid tube of finite length (at least in the course of the cleaning operation) and each of its ends is communicatively connected with a different port of the valve body prior to start of the cleaning operation. As a rule, the cleaning agent is water which is supplied to the inlet by a faucet with the interposition of a suitable supply conduit. Spent cleaning agent which leaves the body of the valve by way of the outlet can be discharged into a sink or the like. The pressure of cleaning agent suffices to entrain the cleaning elements which impinge upon filters, one at each end of the piston, so that the flow of liquid cleaning agent through the one filter is reduced accordingly with the attendant buildup of liquid pressure which causes the piston to move to the other position. Thus, the cleaning elements initiate a shifting in the position of the piston whenever they complete their travel through the pipeline.
The aforementioned housings of the cleaning apparatus which is disclosed in the German publication comprise cylinders which are made of glass and are connected to the body of the valve, and flanges which are connected with the respective ends of the pipeline. Each flange is connected to the body of the valve by means of several screws or bolts so that each cylinder is confined between the valve body and the respective flange. Each flange has an externally threaded nipple which can be connected with the respective end of the pipeline by a manually operated coupling device. The cleaning elements are normally relatively small spheres which are made of foam rubber or the like and whose diameters are at least slightly smaller than the inner diameter of the pipeline. The inner diameter of each of the aforementioned nipples matches or approximates the inner diameter of the respective end of the pipeline.
When a cleaning operation is completed, the operator dismantles one of the housings by detaching the respective flange from the body of the four-way valve so as to gain access to the cleaning elements in the respective glass cylinder. The thus removed cleaning elements must be stored in a separate place for renewed use. Such cumbersome and time-consuming treatment of cleaning elements upon completion of each cleaning operation is considered necessary in order to avoid partial or complete drying of the cleaning elements after the cleaning agent has been drained out of the apparatus. Dried or partially dried cleaning elements could gather bacteria from the surrounding atmosphere and could contaminate the cleaning agent in the course of the next cleaning operation. As a rule, the cleaning elements must be extracted by a specially designed tool, especially if they are to be removed while still in expanded (moist or wet) condition.
Removal of impurities which gather along the outer sides of the aforementioned filters also presents numerous problems and is a time-consuming operation. Still further, the just described conventional apparatus is designed for the cleaning of pipelines with ends having a predetermined inner diameter. If the inner diameters of the ends of a pipeline are different, it is necessary to employ a second apparatus with housings including flanges having nipples of appropriate size so as to be connectable to the ends of the pipeline. This means that, when the pipelines for the conveying of beer and/or other beverages in a restaurant, bar or a similar establishment require cleaning, the agency in charge of cleaning must send at least two different apparatus, or the owner of the establishment must purchase several apparatus, because pipelines which convey beer from the barrels to the taps often employ hoses or tubes having an inner diameter in the range of 7 mm in contrast to the conduits for alcohol-free beverages whose diameter is normally in the range of 10 mm.
A somewhat similar apparatus was offered for sale under the name "Fasil" by Friedrich Hueber, Munich, German Federal Republic. This apparatus employed a manually operated valve for reversing the direction of flow of a liquid cleaning agent through the pipeline. The cleaning elements had to be inserted into one of the glass housings prior to start of each cleaning operation.